Added test for US flag

- ensures that #243 is fixed

Tests/W3CTestSuite/svg/__Flag_of_the_United_States.svg

+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="1235" height="650" viewBox="0 0 7410 3900">
+<rect width="7410" height="3900" fill="#b22234"/>
+<path d="M0,450H7410m0,600H0m0,600H7410m0,600H0m0,600H7410m0,600H0" stroke="#fff" stroke-width="300"/>
+<rect width="2964" height="2100" fill="#3c3b6e"/>
+<g fill="#fff">
+<g id="s18">
+<g id="s9">
+<g id="s5">
+<g id="s4">
+<path id="s" d="M247,90 317.534230,307.082039 132.873218,172.917961H361.126782L176.465770,307.082039z"/>
+<use xlink:href="#s" y="420"/>
+<use xlink:href="#s" y="840"/>
+<use xlink:href="#s" y="1260"/>
+</g>
+<use xlink:href="#s" y="1680"/>
+</g>
+<use xlink:href="#s4" x="247" y="210"/>
+</g>
+<use xlink:href="#s9" x="494"/>
+</g>
+<use xlink:href="#s18" x="988"/>
+<use xlink:href="#s9" x="1976"/>
+<use xlink:href="#s5" x="2470"/>
+</g>
+</svg>
\ No newline at end of file